Three-way stopcock



FIG. 1 is a perspective view of a three-way stopcock showing our new design;

FIG. 2 is a front view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a left side view thereof;

FIG. 5 is a right view thereof:

FIG. 6 is a top view thereof; and,

FIG. 7 is a bottom view thereof.

The broken lines show portions of the three-way stopcock that form no part of the claimed design. 

CLAIM The ornamental design for a three-way stopcock, as shown and described. 